I've gone through the same improvement business as a recent beginner and tried out a lot of books. The choice depends how much effort/time you want to dedicate and if you want a quick boost or want to lay the foundations for the long term. Assuming the latter, the following are gold:
Polgar Chess: 5334 Problems
Pandolfini's Endgame Workshop (I love this book, it explains things so much better than its rivals). If you want to be good many players I respect recommend serious endgame focus early on, it teaches you a lot of skills aside from the specific endgames you study.
Chernev Logical Chess Move By Move
If you're more after quick results, a good all-round introductory text is Play Winning Chess by Yasser Seirawan, and the more time you then spend on tactics after that the better. You could always move onto the above books after - don't assume you know the fundamentals until they're second nature. If you do you'll plateau later on. For a pure tactics book if you don't want to commit to the big Laszlo Polgar book above Chess Tactics for Champions by Susan Polgar is my favourite. Do those questions until the tactical motifs are second nature. Don't succumb to web based tactics training with 50,000 problems or whatever, it's more efficient to see the same problems again and master them. I haven't nearly completed all the books I've mentioned above, these "basics" take you to a good level if you take the trouble to learn them rather than skipping ahead...
Hope that helps.
Hi everyone, I'm a beginner with a current score of just under 1200. I'm after a good book that will teach me the basics and help to boost my score. Does anyone have any good recommendations? Thank you.